How to Shoot with a Reflex Sight (Red Dot)

When the Army adopted reflex optics, many units were slow to use them. Aimpoints sat on shelves in arms rooms while soldiers trained with iron sights. After all, the joes might break them! And anyway, the Sergeant Major never shot with optics when he was a young soldier, so neither will his soldiers.

Then we went to war.

Suddenly, many soldiers found themselves with an unfamiliar piece of equipment sitting on top of their rifles and carbines. NCOs had to quickly train their soldiers on their proper use. Problem was, many NCOs had never been trained. I began to overhear some really weird stuff as NCOs struggled help their troops.

“The dot replaces the rear sight. Put the dot on the front sight post, put the front sight post on the target, and squeeze the trigger. That’s called co-witness shooting.”

WHAT?! Other NCOs and I spent a lot of time trying to teach soldiers the proper use of Aimpoints and EOTechs and trying to combat improper training. Now I find that most civilians who ask about purchasing a reflex sight are also asking about their proper use.

Reflex sights work well because aiming is simple.Forget lollypops and 100 meters. Co-witness has nothing to do with proper sight picture. The secret to the reflex optic is this: if you can see a red dot, and the red dot is on your target, the bullet will hit the target. No aligning sights. No sharp front sight and blurry target. No critical cheek weld. Here is how it’s done:

With the weapon on safe at the ready, identify and focus on a target. Keeping both eyes open, bring the weapon up to the firing position. As the sight comes up in front of the eyes, a red dot will appear in front of the eyes. When the red dot reaches the point of aim, switch to fire and engage the target. Both eyes remain open and the focus never moves from the target.

Aiming becomes a quick reflexive action.

Always keep the reticle brightness adjusted as low as possible for lighting conditions. This will give a clearer sight picture and obscure the target less. A common complaint I hear about red dot optics goes like this, “On sunny days in Arizona, I have to turn the brightness almost all the way up in order to see the reticle.” Well, Duh. That’s what that knob is there for, so use it. Turn it low in the dark, and high in the sunlight or snow. If you are using night vision, you will need an optic that has lower intensity settings for night vision use. Otherwise, if using a monocular (ANPVS-14, etc.), put the monocular on the non-firing eye and make sure it is aligned well (no double image when looking at a distant light, for example). Then use the naked eye for the optic, and the two images will be super-imposed.

How to ZeroZeroing a red dot sight is the same as zeroing any rifle scope, with the additional process of zeroing back-up iron sights if you have them. I prefer to boresight before I go to the range. Once you have your boresighted weapon on the range, either remove the optic if necessary, or sighting through it, zero the iron sights. While zeroing the iron sights, leave the optic turned off and ignore it. Once iron sights are zeroed, flip them down, if possible. Turn the optic on and zero according the the manufacturer’s instructions. While zeroing the reflex sight completely ignore the iron sights. They are two different sighting systems and have nothing to do with each other. The iron sights are not zeroed to the dot, and the dot is not zeroed to the iron sights.

If both your iron sights and your red dot sight are zeroed well, don’t worry about where they are in relation to each other. I have observed great frustration on the range when soldiers tried to get the red dot to line up on top of the front sight post and still have the weapon shoot to point of aim. I had an M68 (Aimpoint) on an M4 that, when zeroed, positioned the dot above and to the right of the front sight tower. Both iron sights and the Aimpoint hit dead on.

But they are only accurate for short range shooting, right?I hear this repeated over and over again by soldiers, on forums, and in magazines. The Government nomenclature for the Aimpoint sight was the M68 CCO. Many instantly assumed the acronym stood for Close Combat Optic. Maybe the word close was just easier to spell than collimating. Whatever the reason, this designation caught on and led to the often repeated myth that reflex sights loose all accuracy when used for targets over 100 meters away. If a sighting system is accurate at 50 meters, why would it not be accurate at 250 meters? It should still be as accurate at 800 meters, but at extended ranges we begin to get into the issue of effectiveness. The sight won’t loose accuracy at long ranges, but at a certain point, depending on skill and eyesight of the shooter, magnification may increase effectiveness. Effective is not the same as accurate.

The original designation for the M68 was Collimating Combat Optic. This simply meant that the sight collimates a projected reticle (aligns the light so that the beam does not spread) and reflects it off a mirror that is designed to reflect one specific colour of light. Thus, while the reticle is reflected back toward the eye, the image from the front of the sight is allowed to pass through with no magnification. This puts a reticle on the same focal plane as the target, allowing the eye to focus on both the target and reticle simultaneously. Parallax is almost eliminated in quality sights. The result is that close targets can be instantly targeted and hit, no matter where the head is in relation to the weapon. If the dot is visible, placing it on the target will result in a hit. At longer ranges, cheek weld (position of the cheek against the stock) becomes more critical. Minor parallax can cause insignificant deviations in point of impact at close ranges, but at long ranges this error is magnified. The solution is to pay more attention to eye position, as you do when shooting with iron sights or a standard rifle scope.

How do I get my reflex sight to co-witness?Much discussion revolves around how to get particular reflex sights, back-up iron sights, and mounts to all work together to co-witness. Part of the problem is that most people seem to feel that that it is absolutely necessary that the iron sight picture to correspond exactly to the red dot reticle. In other words, when the two systems are viewed together, the red dot is in the exact point of aim of the iron sights. Many people even recommend using the two together. My idea of the ideal use of back-up iron sights is simply the ability to use the iron sights through the optic, should the optic become inoperable. I prefer the iron sights low in the reflex sight picture if the front sight does not flip down, so that the sight picture is obstructed as little as possible. What you do not want to see is a red dot centered squarely somewhere on the back of a front sight tower – the dot must be above the front sight or the target will be obscured. I see no reason to spend a bunch of money trying to shim things around to get a dot perfectly lined up with iron sights I hope not to use anyway. The purpose for co-witnessing is to use one sighting system to verify the zero of the other. If this is important to you, than do it. Otherwise don’t worry about it. If the two systems are set up to co-witness, and one day they don’t line up, which one moved? You still have to go to the range to figure it out. Remember that, depending on the shooter and the sight, even if everything is set up correctly, the two systems may not seem to line up exactly when both are zeroed.

What type of reflex optic should I buy?This depends on the type of firearm, the type of shooting you will do, and the price you are willing to pay. Whether or not you will be shooting with night vision can also be a determining factor. The main thing to remember is that you get what you pay for, and this is especially true for optics. Optics are expensive to build, and low price usually requires low quality.

I have more experience with Aimpoint optics than any other reflex sight systems. I like Aimpoints a lot and have had trouble with only one (an issue sight that someone had damaged). All others have worked very well. They are easy to use and can withstand a lot of abuse. The only problem I have had is that I often bumped the power switch and activated the sight. I learned to check it often to avoid draining the batteries when it was not in use. Newer Aimpoints have much longer battery life.

My favorite reflex optic is the Mepro M21. It is ideal for very fast CQB type shooting. It also allows more radical shooting positions than some other types of sights. The Mepro M21 is available with several types of reticles for different purposes and preferences, including dot, bullseye, open X, and triangle. The best thing about the Mepro M21 is that it requires no batteries. There are no electronics or switches – the sight is always on. Using ambient light through a fiber optic collector system, the reticle automatically adjusts to ambient light. When you go from a dark room to a desert street, the reticle becomes brighter. When you enter another dark building, the reticle dims appropriately. In total darkness, the reticle is illuminated by tritium and the sight is night vision compatible. The Mepro M21 is built like a tank, and due to a design that does away with electronics, batteries, and has no delicate internal moving parts, it is the ideal combat optic. It is impervious to water, sand, cold, etc. It can be mounted on your weapon with the well-designed quick-detach mount, zeroed, and basically forgotten – you simply know that any time you pick up your weapon the sight is on and good to go. It is the standard issue sight for the Israeli Defense Forces.

The EOTech sights are similar to the Mepro M21 sights in how they work and look. The difference is that EOTechs require batteries and have to be turned on and off, and the brightness must be adjusted. There have been some issues with some sights losing power under recoil, but the issues have been addressed by EOTech, and overall, they are good sights.

For pistols, or for piggyback use with a higher magnification optic, there are small reflex optics available from several companies, including Docter Optic, JP Enterprises, Inc., Trijicon, Burris, Sight Mark, and others. The Trijicon RMR sight is the only one that the manufacturer says can get wet, and I have seen them banged around quite hard, so it would be my choice for any heavy use.

There are quite a few nice looking reflex optics out there that we have not had the opportunity to test, but as we do, we will let you know what we think of them. If you have a comment on an optic you have used, we would be interested to hear it.

I gained a lot of knowledge about this new technology from this article. I am rigging up a system for my shotgun for turkey hunting and this makes a lot of sense to me since I want a wide field of vision.
Thank you,

Thanks for this info. Great, easy to understand article. Found this while trying to figure out how to zero my new sight. Like your other information and your work looks incredible. Keep up the writing.

Thanks for the great article! I found this article while doing a search to understand why there would be any significance to co-witnessing since the dot and the front sight post don’t line up with the red dot on POI. I was thinking that ideally, I wouldn’t even be able to see the front sight through the optic, but it’s a fixed sight. It seems the guys at the gun store counters may not have ever used the sight, as I was told if everything is correct, the red dot should be an absolute co-witness sitting right on top of the front sight post. I thought I had a problem since my red dot is high and to the right.